U.S. Pat. No. 5,953,713 (Behbehani et al.), incorporated herein by reference, discloses a method for treating sleep disordered breathing comprising measuring a respiration-related variable at an interface placed over a patient's airway coupled to a pressurized gas, feeding cepstrum data obtained from the respiration related variable(s) into an artificial neural network trained to recognize patterns characterizing sleep disordered breathing; supplying pressurized gas to the patients airway in response to recognition of the artificial neural network of sleep disordered breathing. The sampling frequency of the pressure transducer's output disclosed in the preferred embodiment is 512 Hz. A Fourier transform is calculated every {fraction (1/16)} second using a 32 sample values window.
Another aspect of frequency analysis is that, on the one hand, the precision is proportional to the number of input data but that, on the other hand, the response time is correspondingly increased. While high precision is welcome since rather small changes in breath pattern can be detected, a slower response increases the risk of progressive deterioration of the airway aperture, and thereby more severe respiratory disturbance before the patient is aroused. Other methods of detecting sleep disorder are based on breath-by-breath analysis.
Alternatively, if adequate treatment is not installed, the patient will be aroused in a more extended time perspective.